If you are drinking green tea when pregnant, you might want to drink less, or
avoid it altogether, especially in the first trimester.

Caffeine

Green tea contains caffeine and tannic acid. High consumption has been linked
to fertility problems.

In particular, caffeine crosses the placenta and has been associated with
spontaneous abortion, intrauterine growth retardation, and low birth weight.

Two studies found that moderate amount of caffeine is safe for those drinking
green tea when pregnant.

A study carried out by the Yale
University School of Medicine found that moderate caffeine consumption by
pregnant woman is not associated with any side effects.

Caffeine can reduce birth weight and cause miscarriage, but this is
significant only for 600 milligrams of caffeine. This is equivalent to 6 cups of
coffee a day.

Another study based in Denmark arrived
at similar conclusion. They interviewed more than 88,000 pregnant women.
Moderate consumption was found to be safe.

However, drinking more than 8 cups or more of coffee a day increases the
chances of miscarriage or still birth by 60%.

Recommendation

Based on these studies, the United Kingdom Food Standard Agency recommends
300 milligrams of caffeine a day as being safe for most pregnant woman. The
United Kingdom Tea Council says this is equivalent to 6 cups of tea a day.

However, their advice does not single out green tea. Given that it is
associated with neural tube birth defect, you might want to drink less or avoid
green tea altogether.

Some experts recommend taking green tea supplements during pregnancy as a way
to avoid caffeine. Exercise caution. These tablets contain a concentrated form of
extract found in many cups of tea. They can be
dangerous to overdose.